Apparatus for dressing involute profiles



J. J. OSPLACK APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet l INVENTOR JOSEPH IOSPL FICK BY fiwalZu-i; M12,

' ATTORNEYS j 2% 1948. J OSPLAQK 2,434,810

APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 2 INVENTOR JOSEPH I 05 4467f BY 9mm, 771M ATTORNEYS APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 3 INVENTOR JOSEPH J. OJPLHC/f BY 0 /&nm 3%}, 711m 1 W ATTORNEYS Jan. 20, 1948. QSPLACK 2,434,810

APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 4 INVENTOR JOSEPH J: OSPL AC/f BY 92...; 9%, M, W

ATTORNEY Jan. 20, 1948. J QSPLACK 2,434,810

APPARATUS FOR DRESSING INVOLU'IE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet s F .0 F #4 g V73 j? L INVENTOR JOSEPH JI'OSPLAC/f ATTORNEYS Jan. 20, 1948. J. J. OSPLACK 2,434,810

APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 6 INVENTOR.

Josskw .x can AC/f m BY A TTOR NE YJ Jan. 20, 1948.

J. J. OSPLACK 2,434,810

APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 7 INVENTOR. JOJfP/f JOSPLACK 9% WW q zzm 4 A TTOR NE Y6 Jan. 20, 1948. J. J. OSPLACK APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 8 ATTORNEY-5 Jan. 20, 1948. J. J. OSPLACK APPARATUS FOR DRESSING INVOL-UTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 9 INVENTOR. JOSEPH J OJPLA CK BY. 5M4, 94.5,, am; v Aw A TTOR NE Y5 Jan. 20, 1948. J. J. OSPLACK 2,434,810

APPARATUS FOR DRESSING INVOLU'IE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 1O Jig x0,

IN V EN TOR.

JOSEPH IO-SPlAC/f I08 BY 952M441, I WW 1 A TTOR NE Y5 Jan. 20, 1948 J. J. OSPLACK APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet 11 2&0

w m m m JOSEPH J. OJPLAC/l BY I M,

WW; A TTOR NE Y5 Jan. 20, 1948. J. J. OSPLACK APPARATUS FOR DRESSING INVOLUTE PROFILES Filed Aug. 18, 1944 12 Sheets-Sheet l2 a/y INVENTOR. JOSEPH .1 OJPLAC/f BY W; WW 2 M A TTOR NE Y5 Patented Jan. 20, 1948 APPARATUS FOR DRESSING INVOLUTE PROFILES Joseph J. Osplack, Detroit, Mich., a'ssignor to Vinco Corporation, Detroit, Mich., a corporation of Michigan Application August 18, 1944, Serial No. 550,087

16 Claims.

This invention relates to apparatus for dressing involute profiles and more particularly concerns improved apparatus for dressing such profiles on the cutting faces of grinding wheels employed in grinding gears, splines and other involute elements.

An object of the invention is to provide apparatus which is inherently capable of accurately dressing surfaces, such as the cutting faces of a gear grinding wheel, to a true involute profile without the use of any special templates, jigs, or other preformed means having involute curvature. In other words, the involute dresser of the present invention is inherently capable of producing true involute motion of the dressing or cutting point.

The objects of the invention further include the provision of apparatus of the type described which is adjustable to dress any involute profile within a wide range of sizes and which can be rapidly and accurately adjusted to such different sizes by operations involving no more compli-- cated steps than the setting of linear distances between elements. A further object of the invention is the provision of an involute dresser employing a plurality of cutting points so manipulated as to be capable of simultaneously shaping or dressing two adjacent involute profiles such as the opposite cutting faces of a gear grinding wheel. Another object of the invention is the provision of an involute dresser capable of cutting or dressing a'surface to a curvature that is basically involute but is modified to provide a recessed or raised area, as desired, which may also have'involute curvature, on the gear tooth surface at and adjacent the pitch circle of the gear, or at any desired point on the involute profile. The objects of the invention further include the provision of an involute dresser in which the cutting or dressing point or points are so moved during the dressing operation that their axes are at all times tangent to the base circle of the involute profile being dressed or cut. The invention also provides mechanism for moving and reversing the direction of movement of the dresser points without shock, dwell or other sudden disturbance, whereby chattering, jumping or other irregular movement of the points and resulting inaccuracy of the dressing operation is avoided.

The above and other objects of the invention are achieved in general by providing mechanism including a plate or equivalent element mounted to turn about a fixed axis'concentric with the'basc circle of the gear or part being finished, a cutting connected to the point.

or dressing point or tool such as a diamond point dressing element slidably supported on the plate to move along a straight path tangent to a circle concentric with the plate axis, and mechanism for simultaneously turning the plate about its axis and moving the point along a straight path relative to the plate at a rate directly proportional to the rate of movement of the plate about its axis.

In a preferred embodiment of the invention, two oppositely disposed points are thus slidably mounted on a single plate and the plate is oscillated about its axis by a crank motion mechanism. Sliding motion of the points relative to the plate is produced by a connection between the plate and a stationary part. In one embodiment, the stationary part comprises a toothed gear surface concentric with the plate axis, and pinions rotatably supported by the plate engage this surface and are turned when the plate turns. Rotary movement of each pinion is translated to sliding movement of the corresponding point by suitable mechanism which may include a sliding cam bar having a plane surface set at an angle to its path of travel and operating a cam follower Means are preferably provided for adjusting the angle of the cam bar, whereby the rate and extent of movement of the point may be variably adjusted. In a preferred form of the invention, the connections to the stationary part are separable, and the points and their sliding supports and operating mechanisms are adjustably movable circumferentially of the plate to permit easy and accurate setting of the starting positions and the angles of stroke of the points, as well as the tooth thicknesses of the involute profiles cut or dressed. In one form of the invention, a cam bar having an offset area on its follower engaging surface produces motion of the point to cut or dress a modified involute profile having a raised or depressed portion at and adjacent to the pitch circle, of the involute gear tooth or at any desired position on the involute profile. In accordance with another modification of the invention, circular cams are employed in place of the plane or fiat surfaced cam bar construction above referred to.

Other objects, advantages and characteristic features of the invention will be apparent from the appended description of certain specific embodiments thereof.

In describing the invention in detail, reference will be made to the accompanying drawings in which certain embodiments of the invention have been illustrated. In the drawings;

Fig. 1 is a rear elevation. partly in section, of an involute dresser embodying the invention;

Fig. 2 is a plan view of the dresser shown in Fig. 1;

Fig. 3 is a sectional view taken along the line 3-3 of Fig. 1 and viewed in the direction of the arrows;

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 1 and viewed in the direction of the arrows;

Fig. 5 is a sectional view taken along the line 55 of Fig. 1 and viewed in the direction of the arrows;

Fig. 6 is a sectional view taken along the line 6-6 of Fig. 5 and viewed in the direction of the arrows;

Fig. 7 is a sectional view taken along the line 1-1 of Fig. 6 and viewed in the direction of the arrows;

Fig. 8 is an elevation of the inside face of the cam bar slideemployed inthe dresser disclosed in the preceding figures.

Fig. 9 is an elevation, partly in section, taken along the line 9-9 of Fig. 6;

Fig. 10 is an elevation of the outside face of the cam bar slide shown in Fig. 8;

Fig. 11 is an elevation on an enlarged scale illustrating a modified form of cam bar for producing a modified involute surface;

Fig. 12 is a diagrammatic illustration of a gear tooth embodying the modified involute surface resulting from the use of a cam bar of the type illustrated in Fig. 11;

Fig. 13 is a sectional view taken along the line !3--I3 of Fig. 6 and viewed in the direction of the arrows;

Fig. 14 is a sectional view taken along the line l4-l4of Fig. 13 and viewed in the direction of the arrows;

Fig. 15 is a sectional view taken along the line Iii-l5 of Fig. 13 and viewed in the direction of the arrows;

Fig. 16 is a sectional view taken along the line Ill-l6 of Fig. 13 and viewed in the direction of the arrows;

Fig. 17 is an end elevation of the dresser;

Fig. 18 is an exploded perspective view illustrating the operating mechanism of the dresser;

Fig. 19 is a front elevation of a dresser embodying the present invention set up on a grinder bed in conjunction with a grinding wheel to bedressed and a spline to be ground thereby;

Fig. 20 is an end elevation of the dresser with certain parts removed to show the procedure employed in making certain adjustments thereof;

Fig. 20a is a sectional view taken along the line 20a.20a of Fig. 20 and viewed in the direction of the arrows;

Fig. 21 is an end elevation of the diamond points of the dresser showing a form of diamond point holder employed for large base circle gears;

Fig. 22 is a front elevation of one of the dresser point holders shown in Fig. 21;

Fig. 23 is an end elevation showing a dresser point slide arranged for small base circle gears;

Fig. 24 is an end elevation on an enlarged scale showing the details of one form of diamond point holder employed in the dresser of the present invention; Fig. 25 is a plane view, partly in section, illustrating the diamond point operating section of a dresser embodying a modified form ofthe invention;

Fig. 26 is an end elevation of the dresser mechanism illustrated in Fig. 25;

Fig. 27 is a sectional view taken along the line 2'I2| of Fig. 25 and viewed in the direction of the arrows;

Fig. 28 is an end view of one of the diamond point units of the dresser of Fig. 25 taken in the direction of the arrows 28 on Fig. 25; and

Fig. 29 is an end elevation of the diamond point propelling cam of the mechanism shown in Figs. 25 through 28.

The disclosed embodiment of my improved involute dresser is designed to simultaneously dress involute profiles on opposite faces of a gear grinding wheel. As illustrated in Fig. 19, the dresser. generally indicated at D. may be mounted on a horizontally movable carriage 30, over which the gear grinding wheel 3| is suitably mounted on a stand 32 and arranged to rotate about a horizontal axis extending transversely of the carriage 39. The stand 32 may be suitably arranged to permit vertical movement of the wheel 3i with its axis in the horizontal position shown. The work to be ground is illustrated as a spline 33 and is mounted adjacent the left hand end of the carriage 30 between a tail stock 34 and an indexing head 35. When it is desired to dress the wheel 3| to the desired involute profiles, the carriage 30 is moved to the left to the position shown in Fig. 19 until the diamond points 36 and 36' of the dresser D are in a vertical plane passing through the axis of the wheel 3|, whereupon the wheel is rotated and dressed in a manner to be described. After the dressing operation is completed, the carriage 30 is moved to the right until the involute profiles on the wheel 3| engage the tooth surfaces of the spline 33, whereupon the work is ground by the wheel.

In describing the disclosed embodiments of my improved dresser in detail, the elevation of the dresser presented in Fig. 19 will be termed the front thereof and the opposite elevation the rear thereof.

Referring now more particularly to Figs. 1, 2 and 17, the dresser there illustrated includes a frame 38 suitably bolted to the carriage 30. A horizontal stub shaft 39 is fixed to a part 40 of the frame 38 by machine screws 4| passing through a flange 42 integral with the shaft 39. The shaft 39 forms the main rotational axis of the dresser about which a plate 43 carrying a front dresser unit F and a rear dresser unit R rotates (Figs. 2 and 17). v

The plate 43 is oscillated about the shaft 39 by mechanism to be described and as a consequence of such oscillation, the diamond points 36 and 36' are reciprocated relative to the plate 43 in straight paths tangent.to circles concentric with the axis of the plate and at a rate directly proportional to the rate of movement of the plate about the shaft 39. The reciprocatory movement of the diamond points 36 and 36' is derived from the rotary movement of the plate 43 relative to a fixed part, in the illustrated case, a gear segment 44 secured to the frame part 40 by machine screws 45. In general, the driving connection for each of the diamond points 36 and 36' includes a pinion, 46 or 41, rotatably supported by the plate 43 and engaging the gear segment 44, and acting, through suitable mechanism to be described, to impart reciprocatory movement to the diamond point upon oscillation of the plate 63.

The mechanism for oscillating the plate 43 about the shaft 39 will now be described (Fig. 1) A bushing 48 is fixed to the plate 43 and lies between it and the stub shaft 39. A gear 49 is fixed to the inner face of the plate 43 by the machine screws 58. A short shaft journaled in an extension 52 of the machine frame 88 carries a pinion 58 en aging the gear 48 and a pinion 54 engaging a gear segment 55. The gear segment 55 is journaled on a stub shaft 58 carried by an extension 51 at the front of the frame 88. The segment 55 is reciprocated by a crank 58 fixed to the end of a shaft 58 journaled in a frame part 88. a connecting rod 8| serving to link the crank 58 to the segment 55 as shown in Fig. 3. The opposite ends of the rod 8| are respectively ad- Justably secured to the crank 58 and the segment 55 in order to permit adjustment of the stroke angle through which the plate 48 is reciprocated.

The adjustable connections of the rod N are best shown in Figs, 1, 2, 3 and 4. As shown in Fig. 3, a bifurcated lug 82 is slidably supported in slideways 88 extending lengthwise of the crank 58 by means of a cross member 84. A bushing part 85 is fixed to the lug 82 by a threaded and headed pin 88, and the rearward end of the connecting rod 8| is journaled on the bushing 85 between a washer 81 and a plate 88. The pin 88 clamps the cross member 84 in the ways 88 and so locks the connecting rod pivot in its adjusted position. An index mark 82 on the plate 88 registers with a scale 83 on the face of the crank 58 to indicate the amount of adjustment (Figs. 3 and 4). An adjusting screw I3 threadedly engages the arms of the ing 82 and is journaled in a plate I4 fixed to the inner end of the crank 58. Collars I5 and I8 prevent axial movement of the screw I3 relative to the plate I4, and a knurled knob 11 is fixed to the outer end of the screw as shown. Rotation of the screw I8 moves the lug 82 to various adjusted positions along the crank 58, thereby shortening or lengthening the effective crank arm or throw.

The front end of the connecting rod BI is adjustably secured to the gear segment 55 by mechanism substantially identical with that described for securing the rearward end of the rod to the crank 58. A fixture I2 secured to the gear segment 55 has lon itudinally extending ways I8 slidably supporting a lug I8 to which the journal bushing for the front end of the connecting rod M is clamped by a threaded and headed pin 8|.

An adjusting screw 88 threadedly engages the lug I8 and is journaled in a plate 8| fixed to the front end of the fixture I2. Collars 82 and 88 prevent axial movement of the screw 88 through the plate 8i, and a knurled knob 84 is fixed to the end of the screw. A plate I8 fixed to the lug I8 carries an index mark 88 registering with a scale 'II on the fixture I2.

When the stroke angle is to be adjusted, the crank'58 is fixed in its extreme rearward-position as shown in Fig. 3 by means to be described and the knurled knobs I1 and 84 are turned simultaneously whereby the effective arm of the crank 58 is altered without change in the zero or starting position of the gear segment 55.

A gear 85 is fixed to the shaft 58. Means are provided for temporarily fixing this gear in such positions that the crank 58 is in its extreme rear- 6 By turning the pin 88 through a small angle, it may be extended to engage either one of two diametrically opposite openings in the gear 88, one of which is shown at 88. The pin 88 may be again turned after it is extended to lock the pin in its extended osition. Extension of the pin into one of the openings locks the driving mechanism in one or the other of the positions described.

Any suitable source of power may be employed to drive the dresser mechanism, and an electrical motor may be used for that purpose. In the disclosed embodiment, a hydraulic motor 84 is employed and is suitably mounted with its output pinion 85 in engagement with the gear 85. A hand crank 88 is provided on the motor shaft to permit manual operation of the mechanism. A suitable valve 81 of known construction, operated by a knob 88, controls the fiow of hydraulic fluid through the motor 84.

The mechanism for reciprocating the diamond points 38 and 88' during oscillatory movement of the plate 43 will now be described. Referring first to Fig. 18 which illustrates a part of the mechanism in simplified and exploded perspective, the pinion 4'! is fixed to a shaft 88. The shaft 88 may be considered as journaled in the plate 48. The shaft is actually journaled in a unit that is clamped to the plate 43 as hereinward position as shown in Fig. 3 or in its extreme forward position turned 180 from the position there shown. To this end, a locking pin 88 with 1 a knurled head 81 is s idably carried in an opening through the machine frame adjacent the gear 85. The pin 88 has an H-shaped slot 88 therein and the end of a set screw 88 fixed in the frame engages this slot. The arrangement is such that when the pin 88 is retracted and turned as shown in Fig. 1, it is locked against outward movement.

after described in detail. A pinion I88 fixed to the opposite end of the shaft 88 engages a rack I8I on a cam bar slide I82 which is vertically slid.- able on a slide way I88. A cam bar support I84 is fixed to the cam bar slide I82 and carriesa cam bar I 42 disposed at 'an angle to the path of travel of the slide I82. A roller I88 engaging the cam bar I42 is carried by a pin I81 fixed to a slide, I88 movable at right angles to the slide I82 between the ball slide ways I88 and II I. A spring II'I holds the roller I88 against the cam bar I 42. A diamond slide II8 moves parallel to the slide I88 on the ball slide way I I I and carries the diamond point 38. The slides I 88 and H8 are connected by a multiplying mechanism comprising a lever H2 fulcrumed on a pin H3 fixed in the part I88. The lever H2 has a longitudinally extending central opening H4 into which rollers II 5 and H8, respectively carried by the slide I 88 and the slide II8, extend. With the arrangement described, the diamond slide H8 is moved at substantially three times the speed of movement of the slide I88. From the above description of the mechanism shown in Fig. 18, it is apparent that rotation of the plate 48 about the shaft 88 causes rotation of the pinion 41 engaging the stationary gear segment 44, and the pinion acts through the slide I82, the cam bar I 42 and the roller I88 to reciprocate the slide I 88 and the diamond point slide II8. v

The construction of the diamond point supporting and reciprocating mechanism will now be described in detail. The front and rear dresser units F and R are respectively mounted in frame units I I8 and H9, each of which has an extension, I28 and I2.I, embracing and journaled on the bushing 48 of the stub shaft 38 (Figs. 6, 7 and 17). A cap I85 secured by a screw 248 holds the units I28 and I2I as well as the plate'43 in place on the bushing 48. The construction of the two dresser units F and R is identical, and the details of the rear dresser unit R only will be described, the corresponding parts of the front unit F being designated with like reference characters having distinctive exponents.

The frame unit 8 of the rear dresser unit It bears against the outer face of the plate 43 and is adjustably clamped thereto by the screws I22 and I23 (Fig. 6). The screw I22 threadedly engages the frame H9 and its head rests in an arcuate slot I24 in the plate 43 as shown in Figs. 5 and 6. The screw I23 passes through an arcuate slot I25 in the frame H9 and threadedly engages one of a number of arcuately disposed openings I26 in the plate 43 (Figs. 5, 6, '1 and20) The pinion 41 is releasably secured to the tapered end I21 of the shaft 99 by a cap screw I28. This pinion 41 is preferably formed in two mating parts I29 and I30 adjustably clamped together by cap screws I3I which pass through slots I32 in the pinion part I30 (Figs. 5 and 6). A set screw I33 threadedly engaging a stud I34 fixed to the pinion part I29 and passing through a slot I35 in the part I30 en ages a post I50 on the part I30 to provide accurate relative adjustment of the parts. By slightly circumferentially displacing the pinion parts I29 and I30, all back lash be-' tween the pinion and the gear segment 44 can be eliminated.

The pinion shaft 99 is journaled in a bushing I36 fixed to the unit frame H9 and passing through an arcuate slot I31 in the plate 43. The pinion I extends within the unit frame H9 and engages the rack IN on a movable cam bar slide I02 carried by a slide way I03 fixed to the unit frame II9 (Figs. 6, '7 and 14). The outer face of the cam bar slide I02 carries a cam bar support I04 pivotally connected thereto at I38 (Fig. 10). An arcuate clamp I39 secured by screws I40 releasably locks the lower end of the cam bar support I04 to the slide I02. The outer face of the cam bar support I04 is recessed as shown in Fig 18 and a cam bar It! having a plane cam surface I42 is fixed to one side of the recess as shown in Fig. 10. The cam bar support I04 may be adjusted to various angular positions about its pivot I38 between a set screw stop I43 in the cam bar slide I02 and a reference plate I44 mounted on the opposite side of the slide I02. The angle of the cam bar I is set accurately by inserting a gauge block between the plate I44 and an arcuate surface I45 on the cam bar support I04.

The frame outer face, and two ball slide ways I09 and III are suitably secured to the outer face of the cover (Figs. 6, 13 and 14). The cover plate I46 has a horizontally extending slot I41 therethrough, one end of which is in line with the pivot I38 of the cam bar support I04 when the slide I02 is in its lowest position against the stop I48 as shown in Figs. 7, 9 and 13. The stop I48 is empioyed to set the diamond point at its original position on the base circle. The slide I08 is mounted between balls I49 in the slide ways I09 and III as shown in Fig. 13, and has an integral pin I01 thereon passing through the slot I41 and into the cam bar support recess. A roller I06 rotatably secured to the end of the pin I01 engages the plane surface I42 of the cam bar MI. The arrangement is such that with the cam bar slide I02 at its lowest position against the stop I48, the pin I01 and roller I06 are axially aligned with the axis of the cam bar support pivot I38. This makes it possible at this position to adjustably set the angle of the cam bar without causing movement of the diamond point or slide.

The slide I08 is biased to move toward the center of the plate 43 by a spring II1 which is tensioned between a pin II fixed to the unit cover plate I46 and a pin I52 fixed in and extending II9 has a cover plate I46 on its I 8 transversely of the slide I08 (Fig. 14). The spring I I1 extends through a longitudinal opening I53 in the slide I08 and holds the roller I06 in continuous engagement with the plane surface I42 of the cam bar I.

The outer face of the slide I08 carries an adjustable plate I54 fixed thereto by screws I55 passing through slots I56 as shown in Fig. 16. The plate I54 may be adlustably moved longitudinally independently of the slide I08 by set screws I51 and I58 engaging its opposite ends. The set screw I51 threadedly engages a block I50 fixed to the slide I08 by the pin I52, and the set screw I58 threadvedly engages a bar I60 fixed to the slide I08 through a post I6I. A roller II5 is journaled on a pin I62 fixed to the plate I54. A similar roller I I8 is journaled on a pin I63 fixed to the diamond slide H0. The diamond slide IIO embraces the slide way I I I and travels on the balls I49 as shown in Fig. 13. The lever H2 is pivotally supported on a. pin II3 fixed in the slide way I00 and has a counter weight I64 secured thereto and extending beneath the slide unit as shown in Figs. 13, 15, 16 and 1'7. The longitudinally extending central recess II4 of the lever II2 receives the rollers II5 and H6, and these rollers respectively engage bearing surfaces I65 and I66 in the lever as shown in Fig. 11. In the disclosed embodiment, the distance between the axes of the rollers II5 and I I6 is twice the distance between the axes of the lever pivot pin II3 and the roller II5. Accordingly, the lever II2 multiplies the motion of the slide I08 by three in. transmitting motion to the diamond slide I I0.

In dressing wheels for grinding small gears, multiplication of the slide motion is unnecessary, and the slides I08 and H0 are locked together to move in unison. As shown in Fig. 23, this may be accomplished by a plate I61 suitably fixed to the slide H0 and carrying oppositely disposed set screws I68 engaging opposite surfaces of a pin I10 fixed to the slide I08.

The diamond point 36 is secured to the slide I I0 with its axis parallel to the path of travel of the slide by fixtures illustrated in Figs; 13, 16 and 21 to 24. As best shown in Figs. 22 .and 24, the diamond point 36 is clamped in a groove I1I of a block I12 by a set screw I13, and may be adjustably moved axially by a screw I14 carrying a coneshaped collar I15 engaging the back end of the diamond point 36. The block I12 is secured to the diamond slide IIO by cap screws I16 which engage vertical slots I11 in the block I12 (Figs. 16 and 1'7). The block I12 is adjusted vertically (that is, transversely of the path of the slide I III) by inserting a sleeve I18 of suitable length between a lug I19 fixed to and'extending laterally from the bottom of the slide H0 and the under surface of the block I12. The sleeve I13 is supported and clamped in place by a screw I (Figs. 16 and 23).

Adjustment of the diamond point carrying block I12 transversely of the path of the slide IIO determines the base circle diameter of the gear to be finished by the involute profile dressed by the diamond point. The diamond point carrying block I12 described is suitable for a limited range of base circle diameters, but for relatively large base circles, diamond point supports of greater length are employed. Supports of this type are shown in Figs. 21 and 22. As there illustrated, the support I8I for the diamond point 36 is of considerable length and is provided with long slots I82 for the reception of the cap screws I16. The position of the support I8I is determined by the length of the sleeve I83 clamped by the screw I84 between the bottom of the support I8I and the lug I19 secured to the bottom of the slide I I8.

Suitable reference pins and surfaces are provided for checking the stroke angle of the dresser and setting the tooth thickness of the involute profile dressed. A reference plate I85 is fixed to the upper edge of the plate 43 adjacent the rear dresser unit R, and a part I86 of the plate I85 extends out beyond the outer face of the plate 43, as shown in Fig. 20a. A reference pin I81 is fixed to the dresser frame 38 and extends over the plate I85 as shown in Figs. 2, 4 and 20. Means are provided for securing a pin I88 in a lower position as indicated in Figs. 4 and 20. A reference disc I89 is fixed to the frame H9 01' the rear dresser unit R adjacent its upper edge and beneath the reference plate part I86. As shown in Fig. 20a, the disc I89 may be fixed to a plug I98 secured within an opening I9I in the frame II9 by a screw I92 engaging a. washer I93. A corresponding reference disc I89 is similarly secured to the frame II8 of the front dresser unit F beneath the outwardly extending part I86 of the reference plate I85 (Fig. 20).

In'setting up the disclosed embodiment of my improved involute dresser to dress involute profiles of a predetermined size, the diamond points 98 and 38' are set so as to lie on the base circle of the desired involute profile when the mechanism is in the zero position and in the end of stroke position respectively. For this purpose, sleeves i 18 and H8 of suitable length are inserted beneath the diamond point supporting blocks H2 and I12 as described above. The stroke of the dresser is then adjusted to the desired value by loosening the locking pins 66 and 9t and turning the adjusting screws 13 and 88 until the effective arm of the crank 58 is set to a value to produce the desired angle of stroke of the plate 49, after which the pins 66 and 91 are tightened. This adjustment is made with the crank locked in its most rearward position by insertion of the pin 86 in the opening 98 of the gear 85 (Fig. 1). This position of the mechanism is herein termed the zero position, and with the mechanism so locked, the position of the plate 49 may be checked by measuring the clearance between the reference pin I181 and the top of the reference plate M on the edge of the plate 48 (Fig. 20). This clearance for proper zer position is .050 inch in the disclosed dresser. The stroke angleof the plate 43 may be checked by rotating the gear from the zero position and locking it in the new position by the pin 86. This new position is termed the end of stroke position herein. The stroke angle is then measured by inserting a gauge block of proper length between the reference pin I81 and the top of the plate 1189. If the stroke angle is greater than about 38, the gauge block may be inserted between the plate I85 and a pin in the position indicated at M8 in Fig. 20.

The two dresser units F and'R are then set for tooth thickness. In general, this is accomplished by moving the dresser units circumferentially on the plate 83 was to move the diamond points, 38 and 38, along the base circle a suflicient distance to produce the tooth thickness desired. With the mechanism locked in the zero position as described, the rear dresser unit R is released from the plate 43 by loosening the screws I22 and I23 (Fig. 6) and a gauge block of proper length is inserted between the reference disc I89 on the v 18 unit and the under surface of the outwardly extending part I88 of the reference plate I88 on the plate 48. The rear unit clamping screws I22 and I 23 are tightened when the unit has been moved to the position determined by the gauge block. The front dresser unit F is similarly set for tooth thickness with the mechanism locked in the end of stroke position, and in this case, the length of the gauge block represents the angle of stroke, plus one-half the tooth thickness.

The cam bar angle is set so as to correctly relate the rate of movement of the diamond slide II8 to the rate of rotation of the plate 43. In

setting the cam bar angle of the rear unit R, the

screws I48 of the cam bar support clamp I99 are loosened (Fig. 10) and the pinion 41 is loosened or removed from the shaft 99. The cam bar slide I82 is forced down by hand to its lowest position against the stop I48 (Fig. 13). This places the diamond point 88 on the base circle for which the dresser has been set. The pinion 41 is tightened on its shaft 99 by means of the screw I28. A gauge block of proper length is then set between the reference plate I44 and the arcuate surface I45 on the cam bar support I84, thus setting the cam bar I at the proper angle, whereupon the clamp screws I48 are tightened and the support I84 is thereby locked in its adjusted position. The cam bar angle of the front dresser unit F is similarly set with the mechanism locked in the end of stroke position, the pinion 46 being first loosened, the cam bar slide I82, forced to its lowest position against the stop I48 and the pinion 46 tightened before the cam bar angle is set.

The diamond points 36 and 38' are then set to extend the proper distance from the faces of the blocks I12 and H2 (in the disclosed embodiment, this distance is .7500 inch), the dresser mechanism is unlocked by retracting the pin 88 and the device is ready for operation to dress involute profiles on a grinding wheel 3I which is generally accomplished as explained above.

In operation, the plate 43 oscillates through its stroke angle about the shaft 39, and the diamond points 36 and 36' slide relative to the plate 43 in opposite directions along straight paths tangent to circles concentric with the rotational axis of the plate and at a rate directly proportional to the rate of turning movement of the plate 43 about its axis. This moves the points 38 and 36' in opposite directions along oppositely disposed true involute curves, as illustrated in Figs. 7 and 17. The axes of the points 38 and 36' are at all times tangent to the base circle of the involute being dressed, and the point axes are accordingly normal to the profile that they dress, which results in highly accurate dressing. The crank motion of the drive mechanism produces smooth deceleration, reversal and acceleration of the plate 43 at the zero and end of stroke positions, thus avoiding shock or dwell of the mechanism which would produce inaccuracies.

The above described embodiment of my improved involute dresser produces a true involute profile throughout the gear tooth forming face of the grinding wheel 3I. In certain cases it is deemed desirable to produce a tooth profile having a slightly raised portion at and adjacent the pitch diameter of the gear. A modified gear toothof this type is illustrated in Fig. 12. It has raised portions I94 at and adjacent the pitch circle I95, and these portions as well as the other parts .of the tooth faces have involute curvature. The height of the raised portions I94 above the thereof, which recess departs from a plane surface by the distance I: for a linear distance a so located as to produce a recess in the dressing wheel face at and adjacent the pitch diameter of the gear that the wheel is to dress. When the roller m6 travels along the cam bar E93, it

follows the recess E98 and thus so moves the diamond point as to produce a recess of involute curvature therein which in turn produces the raised portions ia on the gear tooth face. The recess I98 illustrated in Fig. 11 is of exaggerated size for the purpose of illustration. The recess B98 has a plane surface over the distance a, and the raised portion E96 is accordingly of involute curvature at and adjacent the pitch diameter of the gear.

The disclosed embodiment of my improved involute dresser is adjustable to a'wide variety of gear sizes without the use of spare parts. A simplified embodiment of the invention illustrated in Figs. 25 to 29 employs removable constant rise cams to propel the diamond points relative to the face plate, and each set of cams is designed to dress involute profiles for one specific gear design. The frame structure, drive mechanism and face plate of this embodiment are identical with like parts of the previously described embodiment, and the description of these parts will not be repeated. The face plate 202 carries two dresser units F and R. of substantially identical construction and the construc-' tion of the rear unit R only will be described in detail, the corresponding parts of the front unit F being designated with like reference characters having distinctive exponents.

The frame member 2! of the unit R is adjustably movable about the axis of the face plate 200 and is clamped to that plate by the screws 202 and 203 as in the previously described embodiment. The shaft 204 of the split pinion 205 which engages the fixed gear segment 44 is carried in a journal 206 fixed to the frame member '20! and extending through an arcuate slot min the plate 200. A pinion 208 fixed to the outer end of the shaft 204 meshes with a gear 209 fixed to the inner end of a shaft 2 l journaled in the member 20!. The outer end of the shaft 2H) carries an integral head 2H having radially extending recesses 2 l2 in its edge as shown in Figs. 27 and 28. The cam 2l4 carries a'pin M on its inner face, which pin engages one of the recesses H2 and so locks the cam against rotation on the head 2| l. The cam 2! is held on the head 2H by a cap 2l6 secured by a screw 2H. An

extension 218 of the frame member 20l has a bushed opening 2i9 therein adjacent the cam 2M and an opening 220 in the cam, aligned with one of the recesses 2i2, registers with the opening 2i9 when the cam is in the position in which the diamond slide 22l is fully retracted with thediae mond point 222 on the base circle of the involute profile 238 being dressed.

The slide 221 embraces a ball slide way 223 fixed to the frame 2!, and balls 224 are interposed between the slide and the slide way as shown in Fig. 27. A fixture 225 adjustably se-' cured to the outside face of the diamond slide 22l by the screws 226 passing through the slots 227, has 9. depending arm 228 carrying a cam fol. lower pin 229 engaged by the edge of the cam 214 (Figs. 26, 28 and 29). A spring 230, tensioned between a pin 23i on the slide HI and a pin 232 on the member 20l maintains the cam follower pin 229 in engagement with the cam 2M and propels the slide 22l as the cam 2 is rotated in the direction of the arrow in Fig. 26. A stop 233 fixed to the end of the slide way 223 overlaps the end of the slide 22! as shown in Figs. 25, 26 and 28. The diamond point 222 is secured to the slide 22!! by an adjustable block 232 and clamping mechanism identical with that illustrated and described in connection with the first disclosed embodiment of my dresser.

The dresser units R and F are adjustably set circumferentiaily of the plate 200 for proper tooth thickness in the manner described in connection with the cam bar type embodiment, the gauge blocks for this purpose being set between the under surfaces of the reference plat/es 235 or 235' on the plate 200 and the reference discs 236 or 236 on the unit members .20! and 2%. During these operations, the slides 22l and 22i' are locked in their retracted positions in which the diamond points 222 or 222 are on the base circle. This is accomplished by inserting a pin 23? in the aligned openings 2! and 220 (Fig. 2'7). The angle of stroke setting and checking is the same as has been described in connection with the cam bar embodiment.

The operation of the cam type dresser is essentially the same as that of the cam bar type except that the linear motion of the diamond point slides 22l and 22! relative to the plate 200 is produced by the direct action of a constant rise cam on the slide rather than by an angularly dis.- posed cam bar. The diamond points 222 and 222 oscillate in opposite directions along involute curves with their axes tangent to the base circle of the involute at all times while dressing and normal to the profiles dressed, whereby accurate and precise dressing is obtained. The dresser may be adjusted for different gear designs by employing differently shaped pairs of cams in place of the cams 2M and 2M.

I claim:

1. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a, plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis, a circular surface concentric with said axis fixed to said stationary part, and means independent of said plate oscillating means and including a rotary element journaled in said plate and engaging said circular surface for reciprocating said point along said path relative to said plate at a rate directly proportional to the rate of movement of said plate about said axis said rotary element being driven by the oscillation of said plate relative to said circular surface.

2. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis, a toothed sesame said plate oscillating means and including a pinion rotatably supported'by said plate and engaging said toothed gear surface for reciproeating said point along said path relative to said plate at a rate directly proportional to the rate of movement of said plate about said axis.

3. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate,. I

means including a uniformly rotating crank, a rotary part and a link connecting said crank to said rotary part for oscillating said plate about said axis, a toothed gear surface concentric with said axis fixed to said stationary part, means includin a pinion rotatably supported by said plate and engaging said toothed gear surface for reciprocating said point along said path relative to said plate at a rate directly proportional to the rate of movement of said plate about said axis. and means for adiustably varying the efiective length of said crank whereby the angle through which said plate is oscillated may be varied.

4. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means including a uniformly rotating crank, a rotary part and a link connecting said crank to said rotary part for oscillating said plate about said axis, a toothed gear surface concentric with said axis fixed to said stationary part, means ineluding a pinion rotatably supported by said plate and engaging said toothed gear surface for reciprocating said point along said path relative to said plate ata rate directly proportional to the rate of movement of said plate about said axis, and means for adjustably varying the effective length of said crank and the length of said link whereby the angle therethrough which said plate is oscillated may be varied without changing one i of the extreme positions of said plate.

5. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a pair of cutting points respectively slidably supported on said plate to move in a plane normal to said axis along straight paths tangent to a circle concentric with the rotational axis of sa d plate, means for oscillating said plate about said axis, a circular surface concentric with said axis and fixed to said stationary part and means independent of said plate oscillating means including rotary elements journaled in said plate and each engag ng said circular surface for reciprocating said respective points along said paths in substantially the same direction when said plate is oscillated and at equal rates directly proportional to the rate of oscillation of said plate.

6. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a pair of cutting points respectively slidably supported on said plate to move in a plane normal to said axis along straight paths tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about aid axis, a circular surface concentric with said axis'and fixed to said stationary part, means including rotary elements journaled in said plate and each engaging said circular surface for reciprocating said respective points along said paths in substantially the same direction when said plate is oscillated and at equal rates directly proportional to the rate of oscillation of said plate, and means for adjusting said points independently of each other and of the movement of said plate to adjusted positions on said plate circumferentially of said axis while maintaining the path of reciprocatory movement of said points relative to said plate tangent to a circle concensupported on said plate and movable in a plane normal to said axis along a straight path substantially at right angles to the path of said cutting point, a substantially straight cam bar carried by said slide and disposed at an angle to the path of said slide, means movable in a path substantially parallel to the path of said cutting point engaging said bar and connected to propel said cutting point along its path, and means carried by said plate and driven by the relative movement of said plate and said stationary part and independently of said plate oscillating means for reciprocating said slide relative 'to said plate upon oscillation of said plate about said axis, whereby said cutting point is reciprocated.

8. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said, plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis, a slide supported on said plate and movable in a plane the path of said cutting point engaging said bar,

and connected to propel said cutting int along its path, and means carried by said plate and driven by the relative movement of said plate and said stationary part and independently of said plate oscillating means for reciprocating srid slide relative to said plate upon oscillation of said plate about said axis, whereby said cutting point is reciprocated.

9. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis,

a slide supported on said plate and movable in path of said slide, a cam bar follower movable in a path substantially parallel to the path of said cutting point and continuously engaging said substantially plane surface of said cam bar, a driving connection between said cam bar follower and said cutting point and means carried by said plate and driven by the relative movement of said plate and said stationary part for reciprocating said slide relative to said plate upon oscillation of said plate about said axis, whereby said cutting point is reciprocated.

10. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on W said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, a slide supported on said plate and movable in a plane normal to said axis along a straight path substantially at right angles to the path of said cutting point, a substantially straight cam bar carried by said slide and disposed at an angle to the path of said slide, a cam bar follower movable in a path substantially parallel to the path of said cutting point and continuously engaging said cam bar, a motion multiplying mechanism connecting said cam bar follower to move said cutting point and means carried by said plate and driven by the relative movement of said plate and said stationary part for reciprocating said slide relative to said plate upon oscillation of said plate about said axis, whereby said cutting point is reclprocated.

11. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis, arotary cam carried by said plate and driven by the relative movement of said plate and said stationary part, and a cam follower engaging said cam and connected to said cutting point whereby said point is reciprocated upon oscillation of said plate.

12. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis, a circular rotary cam carried by said plate, a circular surface concentric with said axis'and fixed to said stationary part, means including a rotary element journaled in said plate and engaging said circular surface for oscillating said cam upon oscillation of said plate, and a cam follower engaging said cam and connected to said cutting point whereby said point is reciprocated relative to said plate upon oscillation of said plate and said cam.

13. In a device of the character described, in combination, a'stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis log a driven crank arm, a. rotary member and a link connecting said crank arm and said rotary member, means for variably adjusting the efiective length of said crank arm, and means carried by said plate and driven by the relative movement ofsaid plate and said stationary part for reciprocating said point along said path relative to said plate.

14. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentrio with the rotational axis of said plate, means for oscillating said plate about said ams including a driven crank arm, a rotary member and a link connecting said crank arm and said rotary member, means for variably adjusting the efiectlve length of said crank arm and the point of connection of said link to said rotary member whereby the angle of stroke of said plate may be varied without changing one of the end positions of said plate, and means carried by said plate and driven by the, relative movement of said plate and said stationary part for reciprocating said point along said path relative to said plate.

15. In a device of the character described, in

, combination, a stationary part, a plate mounted along a straight path tangent to a circle concentrio with the rotational axis of said plate, means for oscillating said plate about said axis includto rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis including a driven crank arm, a. rotary member and a link connecting said crank arm and said rotary member, means for releasably locking said crank arm in either of its extreme positions, and means carried by said plate and driven by the relative movement of said plate and said stationary part for'reciprocating said point along said path relative to said plate.

16. In a device of the character described, in combination, a stationary part, a plate mounted to rotate relative to said stationary part about a fixed axis, a cutting point slidably supported on said plate to move in a plane normal to said axis along a straight path tangent to a circle concentric with the rotational axis of said plate, means for oscillating said plate about said axis including a driven crank arm, a rotary member and a link connecting said crank arm and said rotary member, means for variably adjusting the efiective length of said crank arm, means for releasably locking said crank arm in either of its extreme positions, and means carried by said plate and driven by the relative movement of 'said plate and said stationary part for reciprocating said point along said path relative to said plate.

JOSEPH J. OSPLACK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,907,065 Halborg et al. May 2, 1933 1,912,410 Shotey June 6, 1933 2,237,975 Wainwright Apr, 8, 1941 2,274,959 Headbloom et al. Mar. 3,1942 

